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Long-reach electronic drive and control

TPG has extensive experience in designing and producing highly specialised drive and control systems.

In this case, the challenge was to manage a high speed permanent magnet motor, located several thousand feet away from the power source. The constraints included physical size (the whole system must fit within a seven inch pipe) and protection from contaminants, high temperature and pressure (the system would be in the path of a hydrocarbon gas stream).

System requirements

  • Rotating machine control at high speed and voltage over long distance
  • High frequency inverter drive and permanent magnet motor design to 50kW, 60,000rpm
  • Medium-voltage power system design to 2.5kV/500kVA
  • Design for high power density
  • Extreme temperatures (+125oC)
  • High pressure environments (to 50 bar)

System characteristics

  • Custom packaging as nothing similar was available
  • Low profile and compact to fit constrained spaces
  • Modular design for ease of assembly and maintenance
  • Enclosed to operate in corrosive, immersed, high temperature, 
  • Proprietary encapsulation method for high thermal load and environmental protection
  • Power line (4km) and CAN bus communications in a custom designed cable

 

TPG engineers produced a working system that was able to control a compressor many thousands of metres below ground level in a flowing gas stream. In doing so they overcame many challenges and developed a bank of experience and methods that can be applied in other remote or difficult environments.

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Motor controller

  • Process receive and transmit signal that govern motor performance
  • Control motor speed
  • Monitors motor orbit (shaft vibration) and temperature
  • CAN communications
  • Distributes various DC voltages to various modules

Gate Drive

  • Convert motor controller low voltage signal to switch IGBT at high voltage
  • Low profile package 10 mm high
  • Multilayer PCB board construction
  • 10kV isolation
  • 4 channels – control up to 4 IGBT switches
  • Up to 3kHz switching frequency
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Inverter H-Bridge

  • Electronic switches to control the flow of current in the motor windings
  • Package designed for harsh environment to withstand external pressure
  • 3.3 kV, 100 A IGBT devices (derating for high temperature operation)
  • Inbuilt thermal management – gas cooled module
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VI Sensor

  • Measure voltage and current across motor phase
  • Low profile spring connector
  • Encapsulated to protect components and provide better heat transfer
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Communications management

  • Modulation and demodulation of digital signals from sensors and control
  • Subsurface system pressure and temperature monitoring
  • Digital signals superimposed over control supply of 300V DC – Communication signals transmitted over supply cables
  • Up to 50 kHz bandwidth
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Surface power converter (rectifier)

  • AC-DC conversion rated to 500kVA with communications system
  • Takes mains voltage at 50/60 Hz and convert to medium voltage DC up to 2800V for DC transmission
  • Compact footprint
  • IP rated to withstand 20-50oC with rain and vibration protection
  • Central controller meets IEEE519 harmonic standard